Mineral resource and ore reserve classification defines the risk
associated with quoted resource tonnes and grades, allowing the
interested party to make a judgement as to the `worth' of the
resource statement. The JORC Code and Guidelines (1992) are
now well entrenched as the foundation upon which gold and base
metal deposits in particular are publicly reported. There are three
categories of resource, namely Measured, Indicated or Inferred
reflecting decreasing levels of confidence. The ore reserve, that
is the economically mineable part of the resource, is classified as
Proven or Probable and can only be drawn from the Measured
and Indicated resource categories. As summarised by Stephenson (1995), resource/reserve
classification has been an issue ever since the earliest days of
mining in Australasia where, like elsewhere in the world, the
industry, for a long time, lacked firm reporting guidelines. Those
currently adopted in Australasia as the minimum standards for
companies reporting to the Australian Stock Exchange (ASX)
have been developed and revised since 1972 by The Australasian
Institute of Mining and Metallurgy (The AusIMM), the Australian
Institute of Geoscientists (AIG) and Australian Mining Industry
Council (AMIC). Debate is now underway in terms of adopting
an international code. The Code specifically does not attempt to regulate either the
classification technique nor the method of estimation of the
resource/ore reserve, but rather places the responsibility for this
task on a `Competent Person' whose experience will decide the
appropriate approach for a given commodity/orebody. The
Competent Person must be a Corporate member of either The
AusIMM or AIG with five years experience `relevant to the style
of mineralisation' under consideration.